RLSA antenna is a popular candidate for many applications such as Direct Broadcast Satellite Reception, Point to Point Microwave Link, RFID and Wimax Application. This is due to its capability of carrying high speed signal with high directivity characteristic and capability of beam steering and beam shaping. This paper will introduce the RLSA antenna designed at the frequency of 26 GHz for wireless backbone application. The antenna design was utilize open ended air gap as a separator between radiation surface and ground plane. The open air gap cavity structure normally implemented in broadband planar antennas. This structure normally provide a wide bandwidth and good return loss on the desired frequency. Therefore, an investigation of this technique and hybrid with FR4 board as a cavity material will be very interesting due to condition of easy to manufacture, lighter the antenna weight and durable. The model of RLSA antenna at 26GHz has been simulated. The results obtained a -25dB of reflection coefficient, 23.68dBi of directivity gain with wide antenna bandwidth capability. This research found an opportunity of utilizing RLSA antenna concept for extreme high frequency band application
